JPH06127983A - Intermediate film for laminated glass - Google Patents

Abstract

PURPOSE:To obtain an intermediate film for laminated glass in which a moire pattern does not generate or the generation of it is decreased, even though plural numbers of projection parts which are regularly arrayed are formed on both surfaces. CONSTITUTION:In the intermediate film for laminated glass which is formed by regularly arraying plural numbers of projection parts 1, 2 on both surfaces of a sheet or a film consisting of a thermoplastic resin, an array axis of the projection part 1 which was arrayed on the one surface of both surfaces and an array axis of the projection part 2 arrayed on the other surface are made to have an angle of 60+ or -3 deg. or 30+ or -3 deg..

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an interlayer film for laminated glass. More specifically, it relates to an interlayer film for laminated glass, which is used as an intermediate layer of laminated glass composed of a laminate.

[0002]

2. Description of the Related Art Laminated glass is a safe glass material which has the characteristics that it has high strength and is not easily broken, and that even if it is broken, fragments will not scatter. Therefore, it is widely used as window glass for transportation equipment such as automobiles and aircraft, and for buildings. When manufacturing this laminated glass, an interlayer film made of a thermoplastic resin having adhesiveness is inserted between two glass plates, and the resulting laminate is first subjected to a pre-compression bonding step to eliminate air remaining between layers ( (Deaeration), and then completely adhere in the final pressure bonding step.

The intermediate film used for the laminated glass is
Good degassing during pre-compression bonding, no blocking between interlayer films during storage, moderate slippage when inserted between two glass plates, and other handling characteristics during storage Good workability during glass production is required. Especially, the degassing property at the time of pre-bonding influences the quality of the laminated glass, and if the degassing is insufficient, the transparency of the obtained laminated glass may be insufficient, or bubbles may be generated in the accelerated test. is there.

The overall performance of the interlayer film including the degassing property as described above depends on the type of the thermoplastic resin as the raw material and the physical properties such as viscoelasticity. The surface shape of the is a major factor in determining its overall performance.

In particular, it is known that it is effective to form a large number of fine irregularities called embosses on the surface of an intermediate film, and an intermediate film having an embossed surface is conventionally used. Examples of the form of embossing include a form in which irregularities are randomly formed and a form in which a large number of grid-like grooves are formed.

[0006] The embossing configuration affects the overall performance of the interlayer film, and is particularly influenced by the shape of the protrusion, the size of the protrusion (diameter of the bottom of the protrusion), the interval (pitch) between the protrusions, and the roughness. large. The protrusions do not necessarily have to be regularly arranged, but when embossing is given by an embossing roll that has been subjected to processing such as engraving, helio etching, or etching, the valley arrangement of the embossing rolls is a random arrangement. A more regular arrangement (mountain arrangement in the interlayer film) may be easier to machine mechanically, and reproducibility of the mountain arrangement may be easier to obtain.

For example, Japanese Examined Patent Publication (Kokoku) No. 1-32776 discloses an intermediate film in which a large number of independent protrusions (embosses) are formed on the surface of a sheet. In this intermediate film, the embosses are regularly arranged and the recesses are aligned, so that the air is easily passed through. With this configuration, the deaeration property in the preliminary pressure bonding step is improved.

[0008]

Although the above-mentioned publication states that the regularly arranged embosses may be formed on at least one surface of the intermediate film, it is necessary to obtain good degassing property during pre-press bonding. It is essential to form embosses on both sides of the interlayer film.

However, if embossing is regularly arranged on both surfaces of the intermediate film, a striped diffraction image called a moire pattern may appear. When this moire pattern occurs, not only does it cause a defect in the appearance of the interlayer film, but also the interference fringes change during the work of aligning the glass plate and the interlayer film, which causes the operator's eyes to be tired and the workability to deteriorate. There was a problem of inviting.

Therefore, the present invention provides an interlayer film for laminated glass in which the appearance of a moire pattern is reduced to such an extent that a moire pattern does not appear or a defect does not occur even if regularly arranged embosses are formed on both sides. The purpose is to do.

[0011]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that even when the embosses are regularly arranged on both sides, the arrangement axes of the embosses have a predetermined angle. The inventors of the present invention have completed the present invention by finding that the moire pattern does not appear or that it does not cause a problem even if the moire pattern appears by setting the difference.

That is, according to the present invention, in an interlayer film for laminated glass in which a plurality of projections are regularly arranged on both surfaces of a sheet or film made of a thermoplastic resin, the projections arranged on one of the both surfaces are formed. The interlayer film for laminated glass is characterized in that the array axis and the array axis of the protrusions arrayed on the other surface form an angle of 60 ± 3 ° or 30 ± 3 °.

In the interlayer film of the present invention, the shape of the protrusions formed on the surface of a sheet or film (hereinafter referred to as a sheet) made of a thermoplastic resin is a cone, a pyramid, a pseudopyramid, a prism, a cylinder or the like. For example, various shapes can be adopted without particular limitation.

Further, the height, the bottom diameter, and the interval (pitch) of the protrusions are degassing properties (sealing property, air retention limit) during the working process, workability (preventing blocking between interlayer films, interlayer film and glass plate). It can be changed as appropriate in consideration of the appropriate slip) and the like, but in order to eliminate the moire pattern, the bottom diameter is preferably small and the pitch is preferably large. Generally, height 5 to 500 μm, bottom length 30 to 9
The range of 00 μm and the pitch of 100 to 1000 μm is preferable, but the range is not particularly limited thereto.

There are various possible regular arrangements of the protruding portions. For example, as shown in FIG. 1, in addition to a regular arrangement in a zigzag lattice shape, a lattice shape in which there is no phase shift in both rows and columns. The regular array of is mentioned. Even if two or more different sizes of embossing are applied to the surface of the sheet in order to improve the overall quality of the interlayer film, including degassing properties, as long as the main embossing is regularly arranged, The effect of the invention can be obtained.

Examples of the method for forming the emboss on the surface of the sheet include, but are not limited to, a method using an emboss roll and a molding method.

The thermoplastic resin used as the material of the sheet includes, for example, polyvinyl butyral, polyurethane, polyvinyl chloride-ethylene copolymer, vinyl chloride-ethylene-glycidyl methacrylate copolymer, vinyl chloride-
Ethylene-glycidyl acrylate copolymer, vinyl chloride-glycidyl methacrylate copolymer, vinyl chloride-
Glycidyl acrylate copolymer, polyvinylidene chloride, polyvinylidene chloride-acrylonitrile copolymer,
Examples of the vinyl resin include polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl acetal-polyvinyl butyral mixture and the like. Among these, polyvinyl butyral, polyurethane and vinyl chloride-ethylene-glycidyl methacrylate copolymer are particularly preferably used.

Next, as a plasticizer to be kneaded with such a vinyl resin composition, for example, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl adipate, diisodecyl adipate, epoxy fatty acid monoester, triester Examples thereof include ethylene glycol-di-2-ethylbutyrate, triethylene glycol-di-2-ethylhexoate, dibutyl sebacate, and dibutyl sebacate, but are not particularly limited thereto. The blending amount of this plasticizer is preferably 20 to 45% by weight based on the vinyl resin.

As a method of molding the above thermoplastic resin composition into an interlayer film for laminated glass, any known method such as a calender roll method, an extrusion method, a casting method, an inflation method or the like can be adopted. Further, at the time of forming the sheet, a heat stabilizer, an antioxidant and the like may be added to the sheet, if necessary. Furthermore, in order to provide high penetration resistance, an adhesiveness adjusting agent, for example, a metal salt may be added.

The interlayer film for laminated glass of the present invention can be used for laminated glass having various laminated structures. For example, glass-intermediate film-glass, glass-intermediate film-glass-intermediate film-thermoplastic resin layer, glass-intermediate film-
It can be used for laminated glass having a laminated structure such as a thermoplastic resin layer, a thermoplastic resin layer-intermediate film-glass-intermediate film-thermoplastic resin, but is not particularly limited thereto.

[0021]

The surface of the intermediate film in which the embosses are regularly arranged constitutes a diffractive surface, and when a set of two diffractive surfaces having slightly different directions or lattice constants is observed with an electron microscope or an X-ray diffraction microscope, it causes a problem. You can observe the moire pattern. This moire pattern is a striped diffraction image having properties similar to moire image interference fringes, and is generated by the mutual interference effect of diffraction surfaces. This moire pattern is also observed when thin cloths having a regular pattern are overlapped and seen through, or when a halftone printing is again applied to a grid screen to form a halftone.

Therefore, we have developed an intermediate film for laminated glass in which embossing rolls can be easily processed, embosses can be formed with good reproducibility, and regularly arranged embosses with no or reduced appearance of moire patterns. As a result of earnest efforts to obtain the above, it was found that the angular difference between the arrangement axes of the embosses formed on the front and back surfaces of the intermediate film is the key to the improvement of the defect due to the moire pattern.

FIG. 1 schematically shows embossing arrangements formed on both front and back surfaces of the interlayer film for laminated glass according to the present invention. The embossing arrangements are formed on the left and right protrusions 1 and the back surface on both sides of the broken line in the figure. The arrangement of the protrusions 2 is shown. Here, the angle difference α between the arrangement axes of the front and back surfaces is 60 ± 3 ° or 30
When it is ± 3 °, no moire pattern is observed or the appearance thereof is significantly reduced.

FIG. 2 schematically shows a state in which the protruding portion 1 formed on the front surface and the protruding portion 2 formed on the back surface are superposed and observed. Inside the polygon (each figure shown by the broken line in the figure) having a diameter that is about twice the interval (pitch) between the protrusions, the interference is limited to a very small value, and even if the entire interlayer film is visually observed, No moire pattern is observed.

[0025]

[Examples] An embossing arrangement, pitch of protrusions, height of protrusions, shape of protrusions, bottom length of protrusions, presence or absence of sub-embossing are set to various conditions to prepare an interlayer film, and a moire pattern is formed. The presence or absence of appearance, the appearance defect of the interlayer film, and the blocking property were examined. In addition, the presence or absence of the appearance of the moire pattern and the appearance defect were visually determined. Further, the embossed shape was observed and the pitch was measured by a microscope, and the surface roughness (protrusion height) was measured using a stylus surface roughness meter. Furthermore, as for blocking properties, the interlayer film is 100 mm x 2
Cut 2 pieces into a 5mm rectangle and stack them, then 2k
After applying a load of g and leaving it for 25 hours, it was evaluated by measuring the 180 ° peeling force (average value of n = 3) by a tensile test. In this case, the larger the value, the larger the adhesive force and the poorer the workability.

[Example 1] An embossed roll was used to form protrusions on both surfaces of a plasticized polyvinyl butyral sheet to prepare an interlayer film. The protrusions are arranged in a regular zigzag pattern, and the protrusions on the front and back sides are arranged with an angle difference of 30 °. Furthermore, random sub-embossing is applied to prevent blocking of the intermediate film and to prevent the leading of sealing during the laminating process. Table 1 shows each condition.

[0027]

[Table 1] In Table 1, the upper and lower tiers of the pitch, height, shape, and bottom length of the protrusions show the conditions for the front and back protrusions of the interlayer film, respectively.

[Example 2] An intermediate film was produced under the same conditions as in Example 1 except that the shape and pitch of the protrusions in Example 1 were changed as shown in Table 1 and the arrangement direction angle difference was set to 60 °. did. [Example 3] An interlayer film was produced under the same conditions as in Example 2 except that the material was changed to polyurethane in Example 2 and sub-embossing was not performed.

[Comparative Example 1] An intermediate film was produced under the same conditions as in Example 1 except that the main embossments were arranged in a staggered arrangement and the arrangement directions on the front and back sides were the same. [Comparative Example 2] An intermediate film was produced under the same conditions as in Example 2 except that the main embossments were arranged in a zigzag lattice and the arrangement directions on the front and back were the same. [Comparative Example 3] An intermediate film was produced under the same conditions as in Example 3 except that the main embossments were arranged in a zigzag lattice and the arrangement directions on the front and back were the same.

Table 2 shows the characteristics of the intermediate films of the above Examples and Comparative Examples.

[0031]

[Table 2]

As can be seen from Table 2, the interlayer films of the respective examples in which the angle difference between the embossing arrangement axes on the front and back sides was set to 30 ° or 60 °, were free from moire patterns and appearance defects. In each of the interlayer films of the comparative examples in which there was no difference in the arrangement axis angle, a moire pattern was clearly confirmed, and a defect in appearance also occurred. It was also confirmed that the blocking property greatly depends on the presence or absence of sub-embossing.

[0033]

As described above, according to the present invention, it is an interlayer film for laminated glass which is formed on both the front and back sides by regular embossing which is easy to process such as embossing roll and has good shape reproducibility. It was possible to obtain an interlayer film for laminated glass in which a pattern did not appear or the appearance was significantly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an arrangement axis direction of embosses formed on both front and back surfaces of an interlayer film for laminated glass of the present invention.

FIG. 2 is an explanatory view showing a state in which embossing arrays formed on both front and back surfaces of the interlayer film for laminated glass of the present invention are superposed.

[Explanation of symbols]

 1, 2 protrusion

Claims (1)

[Claims] 1. In an interlayer film for laminated glass, which comprises a sheet or film made of a thermoplastic resin and a plurality of protrusions regularly arranged on both sides thereof, and an arrangement axis of the protrusions arranged on one of the both sides. An interlayer film for laminated glass, characterized in that an angle of 60 ± 3 ° or 30 ± 3 ° is formed with the arrangement axis of the protrusions arranged on the other surface.